Side-loading counterbalanced industrial lift truck



1962 w. w. CUSHMAN 3,048,293

SIDE-LOADING COUNTERBALANCED INDUSTRIAL LIFT TRUCK Filed Sept. 16, 1960 i Z 4 pi Walton WCLISZJZZSS ATTORNEY United States 3,048,293 SIDE-LOADING COUNTERBALANCED INDUSTRIAL LIFT TRUCK Walton W. Cushman, Washington, DC. Filed Sept. 16, 1960, Ser. No. 56,606 4 Claims. (Cl. 214-730) (Granted under Title 35, US. Code (1952), sec. 266) The invention described herein, if patented, may be manufactured and used by and for the Government for governmental purposes, without the payment to me of any royalty thereon.

The present invention relates to a side-loading counterbalanced industrial lift truck. It has to do particularly, although not exclusively, with a side-loading and unloading industrial fork type lift truck for use in the relatively narrow aisles and passageways of warehouses, factories, and the like, where the use of presently known conventional industrial trucks is not feasible, for the purpose of transporting, stacking, and tiering such articles or objects as bales, boxes,loade d pallets and other articles.

The present invention constitutes an improvement in industrial trucks of the general character of that disclosed by the patent to Ulinkski, No. 2,709,017 patented May 24, 1955.

One of the important objects of the instant invention is to provide a side-loading industrial truck capable of supporting and handling a laterally disposed supported load located beyond, or at, a side of the truck without the danger of the teetering or tilting of said load and truck while the load-supporting means of the truck is disposed in its outer or projected position at a point or location transversely of and beyond a longitudinal side of the truck.

Another object of the invention is to provide a side loading and unloading industrial truck of the foregoing character which is capable of use in the narrow aisles and passageways of warehouses and the like, in which the load-engaging and handling means of the truck is capable of being projected and retracted laterally, or transversely, of the truck, while being restricted in said movements to a straight-line lateral path outwardly and inwardly with relation to a longitudinal side of said truck, and in which the load-engaging and handling means is capable of normal raising and lowering movements; a further object being to provide new and novel so-called lateral counterweight,.or counterbalancing means for the loadsupporting and handling means of the truck and its burden, to thus prevent the danger of teetering, or sidewise tilting of the truck and its load during loading or unloading operations.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claims when considered in connection with the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In said drawing:

FIG. 1 is a fragmentary side elevation, partly in vertical section, of oneform of industrial truck embodying the present invention;

FIG/2 is a top plan view of the truck shown in FIG. 1, with portions of the mast structure of the truck being in horizontal section;

ine

FIG. 3 is a vertical section, partly in elevation, taken substantially along the line 33 of FIG. 1, looking in the direction of the arrows and with the load-supporting and handlingmeans being in laterally projected position;

FIG. 4 is a sectional elevation of the structure seen in FIG. 3, with the load-supporting and handling means in laterally retracted position;

FIG. 5 is a section taken substantially along the line 5-5 of FIG. 1, looking in the direction of the arrows; and FIG. 6 is a sectional view taken substantially along the line 6-6 of FIG. '1, looking in the direction of the arrows.

Before explaining in detail the present invention, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. It is to be understood also that. the phraseology or terminology employed herein is for the purpose of description and not of limitation.

One illustrative embodiment of the industrial truck of the present invention is shown in the drawing, wherein the present improvement is seen in detail, while the more or less conventional lift truck to which said improvement is added and of which it becomes a part, is only fragmentarily illustrated, see FiGURES 1 and 2.

There is shown, fragmentarily, in FIGS. 1 and 2, the front end portion of a more or les conventional industrial lift truck, being indicated as a whole at 10. The front wheels and tires of the truck are shown at 11 and the mast structure at the forward end of the truck is shown as comprising a pair of fixed outer mast members 12 and a pair of slidable inner mast members 12a. These masts, that is, the outer members 12 thereof, are connected by mast-mounting arms 13 (broken away) which extend forwardly from the truck. 10 and rigidly support, in the usual manner, the mast assembly. Extending forwardly from the movable inner mast members 12:: is a pair of arms 14 in the form of substantially L-shaped brackets. These arms serve to carry and support the load-supporting lifting carriage assembly, said assembly being shown as a whole at 15 and including (see FIG. 2) a substantially L-shaped upright frame. The L-shaped frame comprises a vertical portion or plate :16 which extends laterally or crosswise of the truck 10 and spans the space between the mast members, 12, 12a and the front wheels and tires 11, 11. The upright or vertical L-shaped frame also includes a forwardly projecting plate or member 17 which extends at substantially a right angle to the cross member or plate 16. I

One of the important features of the present invention is perhaps best illustrated in FIGURE 2, and consists of a so-called lateral counterweight or counterbalancing member 18 composed of a sheet of armor plate, or mass of steel which is affixed to, so as to form a part of, the forwardly projecting plate or frame member 17 of the L-shaped frame of the lifting carriage assembly. The carriage assembly '15, including its L-shaped frame, is mounted for up and down sliding movement. It is arranged at the front of the vehicle or truck 10 so as to provide at its lead end, means whereby a lifting fork assembly, to be described below, is so arranged and sup- 3 ported as to be projected and retracted at will in a direc tion laterally, or crosswise of the length of said vehicle.

As shown in FIG. 2, a pair of upright angle members 19 is welded to the inner face, or surface, of the forwardly extending frame portion or weighted plate 17. These members rest upon suitable hearings or base-supporting members 29 provided for them. The angle members l9 afford, as will be seen below, supporting means for a pantograph assembly which is indicated as a whole at 50 in FIGS. 1 and 2. The pantograph assembly is shown in the form of a pair of spaced units which are simultaneously operable and each of which comprises crossed scissors-like pantograph arms and 27.

It is to be understood that the fixed portions of the lifting carriage assembly and the two units of the pantograph assembly cooperate with suitable movable means associated therewith to permit the projection and retraction of lifting forks 23, 23, laterally or transversely of the vehicle 10. Such means includes a pair of angle members 21 attached, as by welding, to the rear face or surface of a vertical plate or member 22 adjacent the upright edges thereof, see FIG. 2. Plate 22 thus provides means for mounting and supporting the transversely, or laterally extending and reciprocable lifting forks 23, 23 whose upper end portions 23a, 23a fit over the upper edge of the plate 22, as seen in FIGS. 3, 4 and 5.

With particular reference to FIGURE 3, one of the pairs of pantograph units is clearly shown in its extended or projected condition. As shown, each unit comprises a pair of scissors-like crossed parallel arms 25 and 27, through the crossed centers of which a pivot shaft 9 extends. The pantograph arm 25 carries at its outer end a short shaft 24 which is adapted to travel up and down in a vertical slot 21a formed in the supporting angle member 21. The opposite or inner end of the arm 25 is mounted on a short shaft 24a which has its bearing in a bracket, or extension 17a, carried by the upright angle 19. The other arm 27 of the pair, at its forward end, is mounted upon a short shaft or pivot pin 26:: carried by a bracket 22a extending from the adjacent face or surface of the vertical plate 22. The opposite or rear end of the pantograph arm 27 carries a short shaft or pin 26 which is adapted to travel vertically in a longitudinal slot 19a formed in the fixed upright angle member 19.

The pantograph assembly 50 of the present invention, illustrated in the form of the two units of four arms each, as shown and as mentioned above, is preferably operated by either hydraulic fluid power or compressed air, the source of supply coming from the vehicle 10 and being operably connected, in any suitable manner, with the pantograph assembly 50. As shown in FIGS. 1, 2, 3, and 4, a vertical or upright cylinder 30, having a reciprocable piston 29 therein, said piston being mounted on rod 28, receives its motive power fluid from a supply line (not shown) which is connected to a nipple 7 located adjacent the upper end of the cylinder for elfecting the downward movement of the piston 29. Another supply line (not shown) is attached to a second nipple 8 disposed adjacent the lower end of the cylinder 30. Such fluid connections are conventional and need not be shown or described in more detail.

As seen in FIGS. 2 and 4, the various members of the pantograph assembly 50 are in their upright positions, with the laterally adjustable forks 23, 23 and their sup porting plate 22, retracted. In this position of the parts, it will be understood that the piston 29 is at its upper limit of travel, as seen in broken lines, FIG. 4. When it is desired to extend or project the lifting forks outwardly transversely, or crosswise of the vehicle 10, fluid power is admitted through the nipple 7 so as to cause the piston 29 to travel downwardly, thus spreading the several pairs of crossed pantograph arms 25, 27, to move the forks 23, 23 into the projected position in which they are shown in FIG. 3. To retract said forks, it is merely t. necessary to bleed the fluid pressure from above the piston 29 and admit hydraulic or other fluid into the cylinder 3% below the piston 29 by means of the fluid connection with lower nipple 8.

It will be understood that whereas lifting forks 23, 23 have been shown, a lift platform may be substituted if and when desired. Moreover, it is to be understood that the lift forks 23 may be relatively and independently adjusted lengthwise of the supporting plate 22, so as to posltion them where desired.

The L-shaped frame and associated mechanism which comprise the lifting carriage assembly and load-engaging and supporting forks of the present invention, are ca pable of convenient and easy manipulation by the operator of the vehicle 10.

When the forks 23 are projected into the position in which they are shown in FIG. 3, with a load mounted on said forks whether in a lowered or elevated position, there is a preponderance of weight at the left side of the vehicle 10, as viewed in FIGS. 1 and 2. To cornpensate for this and to prevent any possibility of tiltlng or teetering of the vehicle and its burden, the so-called lateral counterweight 18 is provided.

The improved mechanism, or attachment of the present invention is capable of being added to a conventional industrial lift truck without requiring any major reorganization or rearrangement of the parts, or units of said truck. The size of the L-shaped lifting carriage 15 may vary and the length of the lifting forks 23 themselves may also vary, in accordance with the size of the industrial truck to which the invention is applied, and also in accordance with the demands on the equipment.

Whereas the lateral counterweight means 18 is adequate to compensate for the load weight on the lifting forks 23 when they are in their transversely or laterally projected position of FIG. 3, it is not sufiicient to cause any tendency of a preponderance of weight which is apparent at the right side of the vehicle when said vehicle is being propelled with, or without a load.

I claim:

1. A side-loading industrial truck having an upright mast and a slidably mounted upwardly and downwardly movable load-supporting lifting carriage assembly in association with the mast, a generally horizontal load-supporting means associated with the carriage assembly and being projectable only in a path laterally of the truck and outward from said assembly beyond a longitudinal side of the truck, said load-supporting means being retractable only laterally in the opposite direction, said carriage assembly including an upright L-shaped frame disposed at two sides of said mast, a pantograph assembly interconnecting the carriage assembly and said load-supporting means, means for operating the carriage assembly for raising and lowering the same, means for operating the pantograph assembly to project and retract said loadsupporting means, and lateral counterweight means associated with said carriage assembly and carried by one portion of said upright L-shaped frame for counterbalancing a load on the load-supporting means when the latter is in projected position.

2. Structure according to claim 1, wherein said loadsupporting means comprises spaced relatively adjustable load-engaging and supporting forks.

3. Structure according to claim 1, wherein the upright L-shaped frame of the load-supporting carriage assembly has a right angularly disposed side portion extending forwardly from the truck and providing the support for said counterweight means.

4. For use with a side-loading industrial lift truck having a mast and a slidably mounted upwardly and downwardly moving load-supporting lifting carriage assembly in association therewith, a generally horizontal load-supporting means associated with the carriage assembly and being projectable only in a path laterally of the truck and outward from said carriage assembly,

5 beyond a longitudinal side of said truck, said load-supcarriage assembly and mounted upon one portion of porting means also being laterally retractable in said said upright frame for counterbalancing a load on the path in the opposite direction, said carriage assembly load-supporting means when the latter is in projected including an upright L-shaped frame disposed at two position. I s1des of said mast, a pantograph assembly interconnecting 5 References Cited in the file of this patent the carriage assembly and said load-supporting means, means for raising and lowering the carriage assembly and ,UNITED STATES PATENTS load-supporting means, means for operating the panto- 2,709,017 Ulinski Ma 24, 1955 graph assembly to project and retract the load-supporting 2,752,058 Gibson June 26, 1956 means, and a lateral counterweight associated with said 10 2,969,991 Ulinski Jan. 31, 1961 

